function prefix = get_snapshot_prefix(snapshot_name)
%%
% snapshot_name = 'DRRN_pre_VDSR_iter_1500.caffemodel';

% k = strfind(snapshot_name, 'iter_');
% % k2 = strfind(snapshot_name, '.caffemodel');
% prefix = snapshot_name(1 : k+length('iter_')-1);

strs = strsplit(snapshot_name, '_iter_');
prefix = [strs{1} '_iter_'];

